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result(s) for
"Anagnostopoulos, Ioannis"
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Ensemble Deep Learning for Multilabel Binary Classification of User-Generated Content
by
Anagnostopoulos, Ioannis
,
Haralabopoulos, Giannis
,
McAuley, Derek
in
Affective computing
,
Automation
,
Classification
2020
Sentiment analysis usually refers to the analysis of human-generated content via a polarity filter. Affective computing deals with the exact emotions conveyed through information. Emotional information most frequently cannot be accurately described by a single emotion class. Multilabel classifiers can categorize human-generated content in multiple emotional classes. Ensemble learning can improve the statistical, computational and representation aspects of such classifiers. We present a baseline stacked ensemble and propose a weighted ensemble. Our proposed weighted ensemble can use multiple classifiers to improve classification results without hyperparameter tuning or data overfitting. We evaluate our ensemble models with two datasets. The first dataset is from Semeval2018-Task 1 and contains almost 7000 Tweets, labeled with 11 sentiment classes. The second dataset is the Toxic Comment Dataset with more than 150,000 comments, labeled with six different levels of abuse or harassment. Our results suggest that ensemble learning improves classification results by 1.5 % to 5.4 % .
Journal Article
The Effect of Blade Angle Distribution on the Flow Field of a Centrifugal Impeller in Liquid-Gas Flow
by
Anagnostopoulos, Ioannis
,
Kassanos, Ioannis
,
Mentzos, Michalis
in
blade design considerations
,
Bubbles
,
centrifugal pumps
2024
Operating centrifugal pumps under two-phase flow conditions presents challenges such as phase separation, cavitation, and flow instabilities, compromising reliability and performance. A specialized design is crucial to mitigate these issues. This study utilized computational fluid dynamics (CFDs) to understand two-phase flow behavior and assess the impact of different blade geometries on pump performance under such conditions. For this purpose, the inhomogeneous multiphase model was employed, wherein the momentum and continuity flow equations were individually solved for each phase across three different impellers with varying blade angle distributions. The computational results indicated higher gas concentrations on the pressure side of the blade, with gas pocket size correlating with flow rate and inlet gas concentration. The blade angle distribution’s effect was more pronounced with increased gas concentrations, while a tendency of gas bubbles to coalesce towards the impeller shroud was also observed. The presence of gas promoted flow recirculation and separation, substantially reducing impeller performance. Blade angle distribution critically influenced the flow field, affecting flow separation, stability, efficiency, and overall performance, highlighting the importance of optimized blade design for enhanced centrifugal pump performance in liquid–gas two-phase flow conditions.
Journal Article
Social Media Use in Higher Education: A Review
by
Paraskevopoulou-Kollia, Efrosyni-Alkisti
,
Anagnostopoulos, Ioannis
,
Zachos, Georgios
in
Academic Achievement
,
Behavior Patterns
,
Cognitive Style
2018
Nowadays, social networks incessantly influence the lives of young people. Apart from entertainment and informational purposes, social networks have penetrated many fields of educational practices and processes. This review tries to highlight the use of social networks in higher education, as well as points out some factors involved. Moreover, through a literature review of related articles, we aim at providing insights into social network influences with regard to (a) the learning processes (support, educational processes, communication and collaboration enhancement, academic performance) from the side of students and educators; (b) the users’ personality profile and learning style; (c) the social networks as online learning platforms (LMS—learning management system); and (d) their use in higher education. The conclusions reveal positive impacts in all of the above dimensions, thus indicating that the wider future use of online social networks (OSNs) in higher education is quite promising. However, teachers and higher education institutions have not yet been highly activated towards faster online social networks’ (OSN) exploitation in their activities.
Journal Article
Frequent traces of EBV infection in Hodgkin and non-Hodgkin lymphomas classified as EBV-negative by routine methods: expanding the landscape of EBV-related lymphomas
2020
The Epstein–Barr virus (EBV) is linked to various B-cell lymphomas, including Burkitt lymphoma (BL), classical Hodgkin lymphoma (cHL) and diffuse large B-cell lymphoma (DLBCL) at frequencies ranging, by routine techniques, from 5 to 10% of cases in DLBCL to >95% in endemic BL. Using higher-sensitivity methods, we recently detected EBV traces in a few EBV-negative BL cases, possibly suggesting a “hit-and-run” mechanism. Here, we used routine and higher-sensitivity methods (qPCR and ddPCR for conserved EBV genomic regions and miRNAs on microdissected tumor cells; EBNA1 mRNA In situ detection by RNAscope) to assess EBV infection in a larger lymphoma cohort [19 BL, 34 DLBCL, 44 cHL, 50 follicular lymphomas (FL), 10 T-lymphoblastic lymphomas (T-LL), 20 hairy cell leukemias (HCL), 10 mantle cell lymphomas (MCL)], as well as in several lymphoma cell lines (9 cHL and 6 BL). qPCR, ddPCR, and RNAscope consistently documented the presence of multiple EBV nucleic acids in rare tumor cells of several cases EBV-negative by conventional methods that all belonged to lymphoma entities clearly related to EBV (BL, 6/9 cases; cHL, 16/32 cases; DLBCL, 11/30 cases), in contrast to fewer cases (3/47 cases) of FL (where the role of EBV is more elusive) and no cases (0/40) of control lymphomas unrelated to EBV (HCL, T-LL, MCL). Similarly, we revealed traces of EBV infection in 4/5 BL and 6/7 HL cell lines otherwise conventionally classified as EBV negative. Interestingly, additional EBV-positive cases (1 DLBCL, 2 cHL) relapsed as EBV-negative by routine methods while showing EBNA1 expression in rare tumor cells by RNAscope. The relapse specimens were clonally identical to their onset biopsies, indicating that the lymphoma clone can largely loose the EBV genome over time but traces of EBV infection are still detectable by high-sensitivity methods. We suggest EBV may contribute to lymphoma pathogenesis more widely than currently acknowledged.
Journal Article
Modified risk-stratified sequential treatment (subcutaneous rituximab with or without chemotherapy) in B-cell Post-transplant lymphoproliferative disorder (PTLD) after Solid organ transplantation (SOT): the prospective multicentre phase II PTLD-2 trial
by
Dreyling, Martin H
,
Zimmermann, Heiner
,
Anagnostopoulos, Ioannis
in
CD20 antigen
,
Chemotherapy
,
Clinical trials
2022
The prospective multicentre Phase II PTLD-2 trial (NCT02042391) tested modified risk-stratification in adult SOT recipients with CD20-positive PTLD based on principles established in the PTLD-1 trials: sequential treatment and risk-stratification. After rituximab monotherapy induction, patients in complete remission as well as those in partial remission with IPI < 3 at diagnosis (low-risk) continued with rituximab monotherapy and thus chemotherapy free. Most others (high-risk) received R-CHOP-21. Thoracic SOT recipients who progressed (very-high-risk) received alternating R-CHOP-21 and modified R-DHAOx. The primary endpoint was event-free survival (EFS) in the low-risk group. The PTLD-1 trials provided historical controls. Rituximab was applied subcutaneously. Of 60 patients enrolled, 21 were low-risk, 28 high-risk and 9 very-high-risk. Overall response was 45/48 (94%, 95% CI 83–98). 2-year Kaplan–Meier estimates of time to progression and overall survival were 78% (95% CI 65–90) and 68% (95% CI 55–80) – similar to the PTLD-1 trials. Treatment-related mortality was 4/59 (7%, 95% CI 2–17). In the low-risk group, 2-year EFS was 66% (95% CI 45–86) versus 52% in the historical comparator that received CHOP (p = 0.432). 2-year OS in the low-risk group was 100%. Results with R-CHOP-21 in high-risk patients confirmed previous results. Immunochemotherapy intensification in very-high-risk patients was disappointing.
Journal Article
Sequential treatment with rituximab followed by CHOP chemotherapy in adult B-cell post-transplant lymphoproliferative disorder (PTLD): the prospective international multicentre phase 2 PTLD-1 trial
2012
Post-transplantation lymphoproliferative disorder (PTLD) develops in 1–10% of transplant recipients and can be Epstein–Barr virus (EBV) associated. To improve long-term efficacy after rituximab monotherapy and to avoid the toxic effects of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) chemotherapy seen in first-line treatment, we initiated a phase 2 trial to test whether the subsequent use of rituximab and CHOP would improve the outcome of patients with PTLD.
In this international multicentre open-label phase 2 trial, treatment-naive adult solid-organ transplant recipients diagnosed with CD20-positive PTLD who had failed to respond to upfront immunosuppression reduction received four courses of rituximab (375 mg/m2 intravenously) once a week followed by 4 weeks without treatment and four cycles of CHOP every 3 weeks. In case of disease progression during rituximab monotherapy, CHOP was started immediately. Supportive therapy with granulocyte-colony stimulating factor after chemotherapy was mandatory and antibiotic prophylaxis was recommended. The primary endpoint was treatment efficacy measured as response rates in all patients who completed treatment with rituximab and CHOP, per protocol, and response duration, in all patients who completed all planned therapy and responded. Secondary endpoints were frequency of infections, treatment-related mortality, and overall survival. This study is registered at ClinicalTrials.gov, number NCT01458548.
74 patients were enrolled between Dec 12, 2002 and May 5, 2008, of whom 70 patients were eligible to receive treatment. PTLD was of late type in 53 (76%) of 70 patients, monomorphic in 67 (96%) of 70, and histologically EBV associated in 29 (44%) of 66 cases. Four of 70 patients did not receive CHOP. 53 of 59 patients had a complete or partial response (90%, 95% CI 79–96), of which 40 (68%, 55–78) were complete responses. At data cutoff (June 1, 2011) median response duration in the 53 patients who had responded to treatment had not yet been reached (>79·1 months). The main adverse events were grade 3–4 leucopenia in 42 of 62 patients (68%, 55–78) and infections of grade 3–4 in 26 of 64 patients (41%, 29–53). Seven of 66 patients (11%, 5–21) had CHOP-associated treatment-related mortality. Median overall survival was 6·6 years (95% CI 2·8–10·4; n=70).
Our results support the use of sequential immunochemotherapy with rituximab and CHOP in PTLD.
F Hoffmann-La Roche, Amgen Germany, Chugaï France.
Journal Article
The AP-1-BATF and -BATF3 module is essential for growth, survival and TH17/ILC3 skewing of anaplastic large cell lymphoma
by
Scheidereit, Claus
,
Merkel, Olaf
,
Damm-Welk, Christine
in
Activator protein 1
,
Adolescents
,
Anaplastic large-cell lymphoma
2018
Transcription factor AP-1 is constitutively activated and IRF4 drives growth and survival in ALK+ and ALK– anaplastic large cell lymphoma (ALCL). Here we demonstrate high-level BATF and BATF3 expression in ALCL. Both BATFs bind classical AP-1 motifs and interact with in ALCL deregulated AP-1 factors. Together with IRF4, they co-occupy AP-1-IRF composite elements, differentiating ALCL from non-ALCL. Gene-specific inactivation of BATFs, or global AP-1 inhibition results in ALCL growth retardation and/or cell death in vitro and in vivo. Furthermore, the AP-1-BATF module establishes TH17/group 3 innate lymphoid cells (ILC3)-associated gene expression in ALCL cells, including marker genes such as AHR, IL17F, IL22, IL26, IL23R and RORγt. Elevated IL-17A and IL-17F levels were detected in a subset of children and adolescents with ALK+ ALCL. Furthermore, a comprehensive analysis of primary lymphoma data confirms TH17–, and in particular ILC3-skewing in ALCL compared with PTCL. Finally, pharmacological inhibition of RORC as single treatment leads to cell death in ALCL cell lines and, in combination with the ALK inhibitor crizotinib, enforces death induction in ALK+ ALCL. Our data highlight the crucial role of AP-1/BATFs in ALCL and lead to the concept that some ALCL might originate from ILC3.
Journal Article
Derepression of an endogenous long terminal repeat activates the CSF1R proto-oncogene in human lymphoma
by
Callen, David F
,
Stein, Harald
,
Bonifer, Constanze
in
692/420/755
,
692/699/67/1990/291
,
Biomedical and Life Sciences
2010
In this work, Björn Lamprecht
et al
. found that survival of Hodgkin's lymphoma cells requires activity of the growth factor receptor CSF1R. Transcription of the gene encoding CSF1R was unexpectedly discovered to originate in a specific class of long terminal repeat, a type of repetitive element present in the genome. Transcriptional initiation from this class of long terminal repeats was widely activated in Hodgkin's lymphoma cells, which the authors traced to defects in epigenetic silencing (
517–518
).
Mammalian genomes contain many repetitive elements, including long terminal repeats (LTRs), which have long been suspected to have a role in tumorigenesis. Here we present evidence that aberrant LTR activation contributes to lineage-inappropriate gene expression in transformed human cells and that such gene expression is central for tumor cell survival. We show that B cell–derived Hodgkin's lymphoma cells depend on the activity of the non-B, myeloid-specific proto-oncogene colony-stimulating factor 1 receptor (CSF1R). In these cells,
CSF1R
transcription initiates at an aberrantly activated endogenous LTR of the MaLR family (
THE1B
). Derepression of the
THE1
subfamily of MaLR LTRs is widespread in the genome of Hodgkin's lymphoma cells and is associated with impaired epigenetic control due to loss of expression of the corepressor CBFA2T3. Furthermore, we detect LTR-driven
CSF1R
transcripts in anaplastic large cell lymphoma, in which
CSF1R
is known to be expressed aberrantly. We conclude that LTR derepression is involved in the pathogenesis of human lymphomas, a finding that might have diagnostic, prognostic and therapeutic implications.
Journal Article
Modeling Intruder Reconnaissance Behavior through State Diagrams to Support Defensive Deception
by
Belalis, Ilias
,
Spathoulas, Georgios
,
Anagnostopoulos, Ioannis
in
Computer networks
,
Deception
,
Intelligence gathering
2023
Active reconnaissance is the primary source of information gathering about the infrastructure of a target network for intruders. Its main functions are host discovery and port scanning, the basic techniques of which are thoroughly analyzed in the present paper. The main contribution of the paper is the definition of a modeling approach regarding (a) all possible intruder actions, (b) full or partial knowledge of the intruder’s preferred methodology, and (c) the topology of the target network. The result of the modeling approach, which is based on state diagrams, is the extraction of a set of all probable paths that the intruder may follow. On top of this, a number of relevant metrics are calculated to enable the dynamic assessment of the risk to specific network assets according to the point on the paths at which the intruder is detected. The proposed methodology aims to provide a robust model that can enable the efficient and automated application of deception techniques to protect a given network. A series of experiments has also been performed to assess the required resources for the modeling approach when applied in real-world applications and provide the required results with bearable overhead to enable the online application of deception measures.
Journal Article
Frequent ZNF217 mutations lead to transcriptional deregulation of interferon signal transduction via altered chromatin accessibility in B cell lymphoma
by
Hablesreiter, Raphael
,
Hennch, Cornelius
,
Mansouri, Larry
in
Accessibility
,
Acetylation
,
B-cell lymphoma
2023
Recent exome-wide studies discovered frequent somatic mutations in the epigenetic modifier ZNF217 in primary mediastinal B cell lymphoma (PMBCL) and related disorders. As functional consequences of ZNF217 alterations remain unknown, we comprehensively evaluated their impact in PMBCL. Targeted sequencing identified genetic lesions affecting ZNF217 in 33% of 157 PMBCL patients. Subsequent gene expression profiling (n = 120) revealed changes in cytokine and interferon signal transduction in ZNF217-aberrant PMBCL cases. In vitro, knockout of ZNF217 led to changes in chromatin accessibility interfering with binding motifs for crucial lymphoma-associated transcription factors. This led to disturbed expression of interferon-responsive and inflammation-associated genes, altered cell behavior, and aberrant differentiation. Mass spectrometry demonstrates that ZNF217 acts within a histone modifier complex containing LSD1, CoREST and HDAC and interferes with H3K4 methylation and H3K27 acetylation. Concluding, our data suggest non-catalytic activity of ZNF217, which directs histone modifier complex function and controls B cell differentiation-associated patterns of chromatin structure.
Journal Article